Acoustic instrument



Dec. 25 1923. 1,478,574

A. MARR ACOUSTIC INSTRUMENT Filed 001;. 4. 1921 meme o. 25, 1923.

um'reo STATES ALEXANDER ma, or m, mum).

ACOUSTIC mmum'r.

Application fled October 4, 1,021. led-l In. 50').

T 0 all whom it may concern Be it known that I, ALEXANDER MARK, asubject of the King of Great Britain and Ireland, and a resident ofManchester, in.

the county of Lancaster, Engalnd, have invented certain new and usefulImprovements in Acoustic Instruments, of which the following is aspecification.

This invention has reference to sound wave concentrators for acousticinstruments for the transmission of sound, such as for example,telephone transmitters, gramophone and like record producers, dictatingmachines, ear trumpets and the like, of the kind consisting of a conicalor conoidal mouthpiece or equivalent fitted at its larger or soundentering end with a plate or cap provided with a constricted aperture,or apertures and removably mounted on or in the mouthpiece orequivalent.

The object of the invention is to provide an improved removableapertured plate or cap, which, while being equally efficient as platesor caps hitherto proposed, can be readily removed for cleaning orotherwise as occasion requires, and replaced in position.

According to this invention, the concentrator plate or cap (hereinafterin this description and the appended claims referred to as the cap) ismade of elastic material such as india rubber so that when fitted on themouthpiece or equivalent (hereinafter referred to as the mouthpiece) itis stretched or tensioned and securely grips the wall thereof.

In the accompanying drawing, Fig. 1 is a side view and Fig. 2 a frontview of a telephone transmitter the mouthpiece of which is fitted withone form of concentrator ea in accordance with the invention. Fig. 3 1sa view of the inner or rear face of the I teferring to the drawing, 4 isthe transmitter, 5 the usual mouthpiece thereof, and

6 the concentrator cap apertured at 7 The cap is made of elastic indiarubber. and on its inner face is formed with a spigot por tion 8 adaptedto enter the mouthpiece 5, and with a flange 9 spaced from and con-'centric with the spigot portion 8 and adapted to embrace the wall ofthe mouthpiece.

" The spigot portion 8 and the flange '9 are made of such external andinternal sizes and shapes that when the cap is fitted in position, asshown, the spigot portion 8 makes an air-tight joint withthe internalsurface of the wall of the mouthpiece, and the flange 9 tightly gripsthe mouthpiece to retain the cap in position thereon.

The spigot portion 8 is rounded at 10 from the point where its inner endor edge meets or joins the inner surface of the wall of the mouthpiece.

A concentrator cap in accordance with the invention as aforesaid isefficient in use, can

be readily fitted in position and removed therefrom, can be readilycleaned, and is not liable to be broken or damaged.

Instead of the aperture 7 of the cap being of circular shape, asillustrated, it may be of elongated or slotted or any other desiredshape, or a plurality of apertures may be provided in the cap.

What I claim as my invention and desire to secure by Letters Patentis 1. Aconcentrator cap for mouthpieces of acoustic instruments, saidcap being made of elastic material, apertured for the passage of soundwaves, and having an embracing flange adapted to be stretched over theflared end of the mouthpiece so as to be held thereon, said cap alsohaving a short spigot flange extending within the mouthpiece andengaging at its edge with the inner wall of the mouthpiece.

' 2. A concentrator cap for mouthpieces of of elastic material,apertured for the assa-ge of'sound. waves, and having an emgracin flangeadapted tobe stretched over the flare end of the mouthpiece so as to beheld thereon, said cap also having a spigot flange with a concave innerface extendin within the mouthpiece into engagement wit the innerwall ofthe mouthpiece and engaging at its edge with the inner wall of themouthpiece.

3. A concentrator cap for mouthpieces of acoustic instruments, said capfitting over the flared end of the mouthpiece and having a flangeextending into the mouthpiece and terminating a short distance from theflared end, said. flange having a concave inner face.

4. A concentrator cap for mouth ieces of acoustic instruments, said capfitting over the flared end of the mouthpiece and having a flangeextending into the mouthpiece and terminating a short distance from theacoustic instruments, said can being made flared end, said flange havinga concave inner face facing toward the small end of the mouthpiece. V

5. A concentrator cap for mouthpieces of acoustic instruments, said caphaving an elastic flange stretched over'the flared end of the mouthpieceand having a second flange extending into the mouthpiece and terminatinga short distance from the flared 15 having an aperture therein for thepassage of sound Waves and having a flange extending from the inner facealong the inner face of the mouthpiece.

7. A concentrator cap for mouthpieces of acoustic instruments and thelike, said cap fitting over the flared end of the mouthpiece andextending across the flared end, the cap having an aperture therein forthe passage of sound Waves and having a flange extending from adjacentthe aperture to the inner face of the mouthpiece, the exposed face ofthe flange being concave.

In Witness whereof I havehereunto set my hand.

ALEXANDER MARR.

